The present disclosure relates generally to ultrasound imaging systems and methods. In particular, ultrasonographic systems and methods for examining and treating spinal conditions are described.
Various techniques for acquiring images of subcutaneous body structures, such as tendons, muscles, vessels, internal organs, and bone surfaces, are in use today by medical practitioners. Known techniques include x-ray, magnetic resonance imaging (MRI), and radionuclide imaging. X-ray and radionuclide imaging techniques suffer from the drawback of exposing patients to potentially harmful ionizing radiation. MRI techniques can be expensive and therefore unavailable to some patients as a diagnostic tool. Further, MRI is unsatisfactorily slow and provides low resolution images of bone structures.
Another technique for imaging subcutaneous body structures as a diagnostic aid involves using ultrasonographic systems. Ultrasound devices used in ultrasonographic systems produce sound waves at a frequency above the audible range of human hearing, which is approximately 20 kHz. Sound waves between 2 and 18 Mhz are often used for ultrasound medical diagnostic applications. At present, there are no known long term side effects from interrogating the human body with ultrasound waves.
Acquiring images of the spine is one known application for ultrasonographic systems. However, known ultrasonographic systems for spinal examination and treatment are not entirely satisfactory for the range of applications in which they are employed.
Existing ultrasound technology may produce one or more two-dimensional cross-sectional images of a patient's spine. However since many vertebrae may have a similar looking cross section, for a given spinal ultrasound image, it is challenging for operators of existing ultrasound technology to determine where along the spine the image was taken (e.g., which vertebrae is being imaged).
Furthermore, existing ultrasound technology does not have the ability to readily recreate three dimensional representations of bone structures. Further, conventional ultrasound systems do not enable the user to re-identify the position of bone structures externally. Moreover, current ultrasonographic systems generally only represent soft tissue structures in three dimensional space and do not satisfactorily represent bone structures in three dimensions.
Further limitations of conventional ultrasonographic systems relate to their reliance on magnetic positioning systems as opposed to more precise optical tracking systems to determine the patient's and/or the ultrasound transducer's position in space. Compounding the relative imprecision of conventional ultrasonographic systems is the fact that they generally determine position data relative to fixed objects adjacent to the patient, such as chest boards the patient is resting on, rather than relative to targets on the patient's body itself. The precision limitations of current ultrasonographic systems mean that practitioners must rely on external landmarks on the body to locate vertebra in need of treatment, which is prone to error.
Known ultrasonographic systems are typically not configured to automatically match new images of a patient's spine to previously acquired images of the patient's spine. The inability of conventional systems to effectively register new spinal images with previously acquired spinal images limits the practitioner's ability to accurately compare a given segment of the spine over time and to evaluate treatment effectiveness.
How acquired images are displayed by conventional ultrasonographic systems highlights another limitation of conventional systems. For example, conventional systems characteristically display acquired images on a two-dimensional screen. Even systems capable of representing acquired images in three-dimensional space generally do so on a two-dimensional screen, with the associated inherent limitations, and lack means to stereoscopically display the images in three-dimensional space.
Another drawback of conventional systems to examine and treat spinal conditions with ultrasound equipment relates to their inability to adequately extrapolate motion of the spine. Often, conventional ultrasonographic systems are limited to static images of the spine without an effective way to correlate different images of the spine when the patient moves to different positions. The inability to correlate images of the spine in different positions deprives the practitioner of important information regarding how the vertebrae move when flexing, extending, and/or rotating.
Thus, there exists a need for ultrasonographic systems that improve upon and advance the design of known ultrasonographic systems. Examples of new and useful ultrasonographic systems relevant to the needs existing in the field are discussed below.
Disclosure addressing one or more of the identified existing needs is provided in the detailed description below. An example reference relevant to ultrasonographic systems includes U.S. Patent Publication 20110021914. The complete disclosure of the referenced patent application publication is herein incorporated by reference for all purposes.